Chiou Chien-Shun, Wang You-Wun, Chen Pei-Ling, Wang Wan-Ling, Wu Ping-Fuai, Wei Hsiao-Lun
The Central Region Laboratory, Center for Research and Diagnostics, Centers for Disease Control, Taichung City 40855, Taiwan.
BMC Microbiol. 2009 Jun 1;9:115. doi: 10.1186/1471-2180-9-115.
The number of scarlet fever occurrences reported between 2000 and 2006 fluctuated considerably in central Taiwan and throughout the nation. Isolates of Streptococcus pyogenes were collected from scarlet fever patients in central Taiwan and were characterized by emm sequencing and a standardized pulsed-field gel electrophoresis (PFGE) method. National weekly report data were collected for investigating epidemiological trends.
A total of 23 emm types were identified in 1,218 S. pyogenes isolates. The five most prevalent emm types were emm12 (50.4%), emm4 (23.2%), emm1 (16.4%), emm6 (3.8%) and emm22 (3.0%). PFGE analysis with SmaI suggested that, with a few exceptions, strains with a common emm type belonged to the same clone. There were two large emm12 clones, one with DNA resistant to cleavage by SmaI. Each prevalent emm clone had major PFGE strain(s) and many minor strains. Most of the minor strains emerged in the population and disappeared soon after. Even some major strains remained prevalent for only 2-3 years before declining. The large fluctuation of scarlet fever cases between 2000 and 2006 was associated with the shuffling of six prevalent emm clones. In 2003, the dramatic drop in scarlet fever cases in central Taiwan and throughout the whole country was associated with the occurrence of a severe acute respiratory syndrome (SARS) outbreak that occurred between late-February and mid-June in Taiwan.
The occurrences of scarlet fever in central Taiwan in 2000-2006 were primarily caused by five emm types, which accounted for 96.8% of the isolates collected. Most of the S. pyogenes strains (as defined by PFGE genotypes) emerged and lasted for only a few years. The fluctuation in the number of scarlet fever cases during the seven years can be primarily attributed to the shuffling of six prevalent emm clones and to the SARS outbreak in 2003.
2000年至2006年间，台湾中部及全岛报告的猩红热发病数波动较大。从台湾中部猩红热患者中分离出化脓性链球菌菌株，并通过emm测序和标准化脉冲场凝胶电泳（PFGE）方法进行特征分析。收集全国每周报告数据以调查流行病学趋势。
在1218株化脓性链球菌分离物中总共鉴定出23种emm型。五种最常见的emm型为emm12（50.4%）、emm4（23.2%）、emm1（16.4%）、emm6（3.8%）和emm22（3.0%）。用SmaI进行的PFGE分析表明，除少数例外，具有相同emm型的菌株属于同一克隆。有两个大的emm12克隆，其中一个克隆具有抗SmaI切割的DNA。每个流行的emm克隆都有主要的PFGE菌株和许多次要菌株。大多数次要菌株在人群中出现后很快消失。甚至一些主要菌株在流行2 - 3年后也会下降。2000年至2006年间猩红热病例的大幅波动与六种流行的emm克隆的更替有关。2003年，台湾中部及全岛猩红热病例的急剧下降与2月下旬至6月中旬在台湾发生的严重急性呼吸综合征（SARS）疫情有关。
2000 - 2006年台湾中部猩红热的发病主要由五种emm型引起，这五种类型占所收集分离物的96.8%。大多数化脓性链球菌菌株（根据PFGE基因型定义）出现并仅持续数年。这七年中猩红热病例数的波动主要可归因于六种流行的emm克隆的更替以及2003年的SARS疫情。
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